Originally Posted by Churchy

Draw a straight line from MF to a minion she fires upon. Create a 70 degree arc behind that minion, where the midpoint of the arc would be intersected by the line created by MF and the minion. The bounce will hit the target farthest back but still within the bounce range (550 iirc) within that arc.

If there are no targets within the first arc, it will revert to a 180 degree arc centered upon the line created by MF and the minion, hitting the target furthest away from the minion but still in range (550 iirc) within that 180 degree arc.

If there are no targets that fit either criteria, the shot will not bounce.

Hope that clears it up.